SCREW COMPRESSOR

PURPOSE:To prevent a leak of high pressure gas directly to a suction side, by constituting a suction port so that a suction stroke may be finished within a prescribed range of rotary angle of a male rotor. CONSTITUTION:A male rotor 1 is located at a rotary angle of -30 deg., and a compression chamber 4 is located at a position separated from a suction port 9 by a tooth point 15' of a trailing tooth 15 of the male rotor 1, forming the compression chamber 4, and a tooth point 20' of a tooth 20 of a female rotor 2. The compression chamber 4 appears in a delivery side end face when a tooth point 8' of a leading tooth 8 of the male rotor 1, forming the compression chamber 4, reaches the line 7, connecting the centers 5, 6 of the male and female rotors 1, 2, then the rotary angle of the male rotor 1 is -60 deg.. The suction port is closed before reaching a rotary angle 0 deg. of the male rotor, and a leak amount of high pressure gas directly to the suction side can be decreased.